Design, simulation and optimization of multi-layered MoS2 based FET devices

Author(s):  
Agraj Khare ◽  
Priyanka Dwivedi

Abstract Transition-metal Dichalcogenides (TMDs) materials are getting attention in the emerging trends of electronic devices development for a variety of applications. One of such materials is MoS2 which is best suited for developing deeply scaled field effect transistors (FETs). With the plethora of TMDs available, MoS2 is the most widely studied and used material because of its tunable properties like band gap, morphology, optical, structural, electrical, flexible etc. This paper represents the design and simulation aspect of the multi-layered MoS2 Based FET devices. Evidence of change in comparative electrical characteristics of MoS2 based FET devices due to variation of thickness and doping of the gate layer are also presented. In this contribution, we have simulated a full-wave model using the COMSOL Multiphysics module for two different thicknesses 0.7 nm and 1 nm. The FET device with 1 nm MoS2 offers a better dynamic range of operation and has a broader spectrum of threshold potential. The characteristic plots of the 1 nm device showed very less deviation from ideal trends than in the 0.7 nm device. The optimized FET structure offers better performance and efficiency in terms of electrical properties.

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1385
Author(s):  
Nicola Pelagalli ◽  
Emiliano Laudadio ◽  
Pierluigi Stipa ◽  
Davide Mencarelli ◽  
Luca Pierantoni

Two-dimensional (2D) materials with intrinsic atomic-level thicknesses are strong candidates for the development of deeply scaled field-effect transistors (FETs) and novel device architectures. In particular, transition-metal dichalcogenides (TMDCs), of which molybdenum disulfide (MoS2) is the most widely studied, are especially attractive because of their non-zero bandgap, mechanical flexibility, and optical transparency. In this contribution, we present an efficient full-wave model of MoS2-FETs that is based on (1) defining the constitutive relations of the MoS2 active channel, and (2) simulating the 3D geometry. The former is achieved by using atomistic simulations of the material crystal structure, the latter is obtained by using the solver COMSOL Multiphysics. We show examples of FET simulations and compare, when possible, the theoretical results to the experimental from the literature. The comparison highlights a very good agreement.


2016 ◽  
Vol 8 (24) ◽  
pp. 15574-15581 ◽  
Author(s):  
Yongtao Li ◽  
Yan Wang ◽  
Le Huang ◽  
Xiaoting Wang ◽  
Xingyun Li ◽  
...  

Nanophotonics ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 1589-1600 ◽  
Author(s):  
M.A. Khan ◽  
Michael N. Leuenberger

AbstractThe discovery of two-dimensional (2D) materials has opened up new frontiers and challenges for exploring fundamental research. Recently, single-layer (SL) transition metal dichalcogenides (TMDCs) have emerged as candidate materials for electronic and optoelectronic applications. In contrast to graphene, SL TMDCs have sizable band gaps that change from indirect to direct in SLs, which is useful in making thinner and more efficient electronic devices, such as transistors, photodetectors, and electroluminescent devices. In addition, SL TMDCs show strong spin-orbit coupling effects at the valence band edges, giving rise to the observation of valley-selective optical excitations. Here, we review the basic electronic and optical properties of pure and defected group-VIB SL TMDCs, with emphasis on the strong excitonic effects and their prospect for future optoelectronic devices.


2021 ◽  
Author(s):  
Denice Feria ◽  
Sonia Sharma ◽  
Yu-Ting Chen ◽  
Zhi-Ying Weng ◽  
Kuo-Pin Chiu ◽  
...  

Abstract Understanding the mechanism of the negative differential resistance (NDR) in transition metal dichalcogenides is essential for fundamental science and the development of electronic devices. Here, the NDR of the current-voltage characteristics was observed based on the glutamine-functionalized WS2 quantum dots (QDs). The NDR effect can be adjusted by varying the applied voltage range, air pressure, surrounding gases, and relative humidity. A peak-to-valley current ratio as high as 6.3 has been achieved at room temperature. Carrier trapping induced by water molecules was suggested to be responsible for the mechanism of the NDR in the glutamine-functionalized WS2 QDs. Investigating the NDR of WS2 QDs may promote the development of memory applications and emerging devices.


2019 ◽  
Vol 116 (9) ◽  
pp. 3437-3442 ◽  
Author(s):  
Yunfan Guo ◽  
Pin-Chun Shen ◽  
Cong Su ◽  
Ang-Yu Lu ◽  
Marek Hempel ◽  
...  

The 2D van der Waals crystals have shown great promise as potential future electronic materials due to their atomically thin and smooth nature, highly tailorable electronic structure, and mass production compatibility through chemical synthesis. Electronic devices, such as field effect transistors (FETs), from these materials require patterning and fabrication into desired structures. Specifically, the scale up and future development of “2D”-based electronics will inevitably require large numbers of fabrication steps in the patterning of 2D semiconductors, such as transition metal dichalcogenides (TMDs). This is currently carried out via multiple steps of lithography, etching, and transfer. As 2D devices become more complex (e.g., numerous 2D materials, more layers, specific shapes, etc.), the patterning steps can become economically costly and time consuming. Here, we developed a method to directly synthesize a 2D semiconductor, monolayer molybdenum disulfide (MoS2), in arbitrary patterns on insulating SiO2/Si via seed-promoted chemical vapor deposition (CVD) and substrate engineering. This method shows the potential of using the prepatterned substrates as a master template for the repeated growth of monolayer MoS2 patterns. Our technique currently produces arbitrary monolayer MoS2 patterns at a spatial resolution of 2 μm with excellent homogeneity and transistor performance (room temperature electron mobility of 30 cm2 V−1 s−1 and on–off current ratio of 107). Extending this patterning method to other 2D materials can provide a facile method for the repeatable direct synthesis of 2D materials for future electronics and optoelectronics.


2020 ◽  
Vol 15 (6) ◽  
pp. 673-678
Author(s):  
Soo-Young Kang ◽  
Gil-Sung Kim ◽  
Min-Sung Kang ◽  
Won-Yong Lee ◽  
No-Won Park ◽  
...  

Transition metal dichalcogenides (TMDs) are layered two-dimensional (2D) semiconductors and have received significant attention for their potential application in field effect transistors (FETs), owing to their inherent characteristics. Among the various reported 2D TMD materials, monolayer (ML) molybdenum disulfide (MoS2) is being considered as a promising channel material for the fabrication of future transistors with gate lengths as small as ∼1 nm. In this work, we present chemical vapor deposition-grown triangular ML MoS2 with a lateral size of ∼22 μm and surface coverage of ∼47%, as well as a PMMA-based wet transfer process for depositing the as-grown triangular ML MoS2 flakes onto a SiO2 (∼100 nm)/p++-Si substrate. Additionally, we demonstrate the fabrication of an n-type MoS2-based FET device and study its electrical characteristics as a function of the gate voltage. Our FET device shows an excellent on/off ratio of ∼106, an off-state leakage current of less than 10– 12 A, and a field effect mobility of ∼10.4 cm2/Vs at 300 K.


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